1. Field of the Invention
This invention relates to electrical connectors and more particularly to an electrical connector for connection to an edge of a single-sided printed circuit board.
2. Description of the Prior Art
There are a wide variety of electrical connector assemblies which are adapted to be mated to an edge of a printed circuit board. Many of these edge connectors include a mating slot which receives a tongue portion projecting from an edge of a printed circuit board. Many such connectors also include fastening means, such as screws or bolts, for mounting the connector housing to the printed circuit board.
In most such electrical edge connectors which have elongated slots for receiving an edge portion or end of a board, a plurality of terminals are mounted in the housing along the slot, and spring contact portions of the terminals are biased against contact pads on either one or both sides of the printed circuit board. These types of connectors generally suffer from the disadvantage of connector tilting which may cause interruption of the electrical pathway or bending of the contacts. To overcome this problem, many connectors rigidly clamp the board within the connector slot against movement perpendicular to the plane of the board. Such clamping often includes the use of screws traversing holes found in the printed circuit board. Such through-hole clamping means is not suitable for certain manufacturing and assembly processes, such as oven/IR reflow soldering.
Rigidly clamping the connector to the printed circuit board causes a myriad of other problems. Such problems include the spring contact portions of the terminals losing their resiliency and, accordingly, the effective biased engagement with the pads on the printed circuit board. Additionally, problems arise from stress cracks produced in the areas surrounding the fastening means which lock the connector to the board. Such stress cracks may create open circuits if the crack traverses a printed circuit.
To avoid the problems associated with edge connectors, conventional header designs are typically surface mount connectors or right-angle connectors. Surface mount connectors usually use "hooks" to secure the connector to the printed circuit board. This design suffers greatly from connector tilling problems, similar to the previously described edge connectors, as well as problems associated with solder lead coplanarity control. These problems lead to connector manufacturing difficulties and poor solder joint formation during automated soldering processes to couple the solder leads to the solder pads of the printed circuit board.
Right-angle connectors also suffer the disadvantage of tilting as well as kinking of the solder leads which are used to assist in holding the connector upright.
To avoid tilting and kinking problems, these connectors generally utilize screws and mating through holes on the printed circuit board to rigidly couple the connector to the board. Thus, right-angle connectors suffer from the disadvantages set forth above regarding stress cracks as well as manufacturing and assembling difficulties discussed above.
The present invention overcomes the problems set forth above to provide a superior design substitute for surface mount and right-angle printed circuit board connectors.